See instructions): This is a competing continuation application for renewal of a training program in gastroenterology that was first funded in 1999. Since then, 20 trainees have been supported, of whom all but four are in full time academic positions, or full-time research in industry, or still in training. The goal of this program is to provide two or three years of research training for young researchers committed to a career in investigative gastroenterology or allied fields. The types of research training include basic, translational or clinical research, or combinations of these. Trainees may be MDs, MD-PhDs or PhDs who have finished clinical or graduate training and are seeking further research training in gastroenterology. Training will consist primarily of mentored research that will provide intense hands-on experience. An extensive menu of didactic courses, workshops, seminars and conferences will also be provided. Trainees in patient-oriented research will be expected to complete course work and thesis requirements to obtain an MMS, MPH or equivalent degree. All trainees will be expected to submit grant applications for K-series NIH awards or support from research foundations during the 3rd year of research training. Trainees will be supervised by experienced research mentors with a wide range of interests and expertise from basic cellular and molecular biology to clinical research. A training committee composed of Drs. Kelly, Robson, Terhorst and Lament and one or two other training faculty will monitor the overall research training program, select suitable candidates and monitor progress. Trainee research programs will be available in four broad areas that are integrated with clinical centers of excellence in the Division: 1.) Intestinal Infection and Immunity 2.) Liver Injury and Fibrosis 3.) Vascular Biology and 4.) Epithelial Biology. The training program will take advantage of the outstanding Gl research base within the Gl Division, the Departments of Medicine and Surgery and at harvard Medical School and School of Public Health. The training program will also benefit from the availability of a well organized and funded General Clinical Research Center at BIDMC, as well as the close proximity of two Digestive Disease Centers, one at Harvard Medical School and a second at Massachusetts General Hospital. The Gl Division has a good track record of recruitment of female and minority trainees and faculty, and has an active plan for future minority outreach and recruitment. RELEVANCE (See instructions): This program will address a critical issue in medicine in general and gastroenterology in particular: the dwindling supply of well-trained physician-scientists and basic researchers focused on Gl and liver diseases. The program will integrate bench research with clinical questions and problems to better address the information gaps in diagnosis and treatment in our specialty. Our ultimate goal is to produce individuals who are able to compete successfully for start-up research funding and for entry level faculty positions and who continue to exhibit a substantial commitment to basic or clinical research.